1. Field of the Invention
The invention is related to storage of nuclear fuel rods and in particular to a rod arraying system which consolidates two fuel assemblies into the rack space of one standard fuel assembly.
2. General Background
Storage space at nuclear reactor sites is very limited. This results in a need to be able to consolidate nuclear fuel being stored. A consolidation ratio of 2 to 1 can be obtained by disassembling two fuel assemblies and repackaging the fuel into one canister which will fit into the same rack space as a standard fuel assembly. Since there is seldom enough space at a utility to allow horizontal handling of fuel, the majority of existing designs and equipment directed toward fuel consolidation handle fuel in a vertical orientation. In most of these systems fuel rods are pulled or pushed from a fuel assembly in groups or bundles and put into a funnel which reconfigures the fuel rod bundle. Bundles may contain a full complement of rods for a complete fuel assembly or rods from a partial assembly. The funnel is a long device that accepts a rod bundle at one end in the same configuration as it is taken from a fuel assembly (rectangular pitch) and gradually changes the configuration of the bundle into a close packed triangular pitch rod configuration at the other end. The reconfigured rods are then fed into a canister for storage.
This approach to fuel rod consolidation has met with limited success since it does not lend itself to quick recovery from an off normal situation such as a broken fuel rod. The funnel approach does not lend itself to other fuel related operations such as burnable poison rod consolidation and does not support fuel reconstitution, eddy current inspection, and recaging of damage fuel assemblies. It can be seen that a more versatile concept is needed in this area.